The investigation into a January midair collision that killed 67 people near Washington, D.C., revealed an alarming number of recent close calls just outside the nation’s capital.

Helicopter traffic should be permanently banned near Ronald Reagan Washington National Airport during certain periods to alleviate congestion and avoid a repeat of the deadly midair collision that occurred there in January,

The NTSB says the current helicopter routes around the busy airport "pose an intolerable risk to aviation safety" in the wake of January's collision that killed 67 people.